A new mayfly of Heptageniidae (Insecta: Ephemeroptera) in mid-Cretaceous Kachin amber, northern Myanmar

Abstract

Heptageniidae (Ephemeroptera) is found in various biogeographical realms such as the Holarctic, Afrotropical, and Oriental regions, and is considered to be relatively species-rich. However, the family's fossil records are sparse. In this paper, a new genus and species of Heptageniidae, Burmaheptagenia zhouchangfai gen. et sp. nov., is introduced based on a male imago that was found in mid-Cretaceous Kachin amber. The distinguishing features of Burmaheptagenia zhouchangfai gen. et sp. nov. include a mesothoracic furcasternum with a convergent anterior medial depression, a prosternum that is rounded and lacks transverse or longitudinal ridges, a 4-segmented hindtarsus, and the presence of penes with lateral sclerites. This new mayfly displays morphological traits of both Rhithrogeninae and Ecdyonurinae and might be a stem group of the two subfamilies.